More than 140 arrested at North Dakota pipeline site as Native Americans attempt to block construction.

(NBC News) Tensions are high in North Dakota, where the largest Native American protest ever is taking place at the site construction site of a controversial oil pipeline.

Thursday afternoon’s clash between protesters and police spilled into the early morning hours.

More than a 140 have been arrested, but demonstrators promise their fight is not over.

An army of 200 officers cleared demonstrators blocking a highway used to access the Dakota Access Pipeline construction site.

The nearly completed pipeline will cross four states, connecting North Dakota and Illinois with 1,200 miles of pipe.

The $3.8-billion dollar project will be capable of transporting 570,000 barrels of oil a day.

The construction runs along the Standing Rock Sioux Reservation. Demonstrators say it’s destroying sacred land and also threatens to pollute the Missouri River, which provides water to millions of people.